PROJECT SUMMARY More than 100 years of research has shown that the adult central nervous system is incapable of self-repair after injury or disease. Indeed, adults that suffer traumatic spinal cord injuries maintain chronic functional deficits that impact all aspects of their lives. However, increasing evidence suggests that the adult CNS retains the ability to initiate a growth program and functionally re-organize in response to activity, experience and mild trauma. To identify the molecular machinery driving this growth response we completed an unbiased in vivo transcriptomic screen of corticospinal motor neuron during the entire temporally defined course of normal corticospinal tract growth and wiring. We believe that a comprehensive understanding of the transcriptomic signature that underlies all phases of corticospinal tract growth, from outgrowth through axon elongation, pathfinding, target recognition and synapse formation, will guide refined therapeutic intervention to functionally repair the acutely and chronically damaged spinal cord.